Tumor Microenvironment: A Niche for Cancer Stem Cell Immunotherapy

Potential Mechanisms for Immunotherapy Resistance in Adult Soft-Tissue Sarcoma

Soft-tissue sarcomas represent a diverse group of rare malignancies originating from mesenchymal tissue, accounting for less than 1% of adult cancers in the USA. With over 13,000 new cases and around 5350 deaths annually, patients with metastatic soft-tissue sarcomas face limited therapeutic options and an estimated median overall survival of 18 months. While immunotherapy has demonstrated effectiveness in several cancers, its application in soft-tissue sarcomas remains challenging owing to the tumors' largely "cold" immunological environment, characterized by low levels of tumor-infiltrating lymphocytes and a lack of soft-tissue sarcoma-specific biomarkers. This review examines potential mechanisms underlying immunotherapy resistance in soft-tissue sarcomas, including the complex interplay between innate and adaptive immunity, the tumor microenvironment, and the role of immune-related genes. Despite preliminary findings suggesting correlations between immune profiles and histological subtypes, consistent biomarkers for predicting immunotherapeutic responses across soft-tissue sarcoma types are absent. Emerging strategies focus on converting "cold" tumors to "hot" tumors, enhancing their susceptibility to immunologic activation. While research is ongoing, personalized treatment approaches may offer hope for overcoming the inherent heterogeneity and resistance seen in soft-tissue sarcomas, ultimately aiming to improve outcomes for affected patients.

Modeling of cancer stem cells and the tumor microenvironment Via NT2/D1 cells to probe pathology and treatment for cancer and beyond

INTRODUCTION

Unique from the other tumor cells, tumorigenic cancer stem cells (CSCs) manifest as a subpopulation of cells within the tumor that exhibit genetic and phenotypic features and signaling processes, which escape traditional anti-oncogenic treatments, thereby triggering metastases and relapses of cancers. Critical to cancer biology is the crosstalk between CSCs and tumor microenvironment (TME), implicating a CSC-based cancer immunotherapy. Cognizant of CSCs' significant role in cancer pathology and treatment, finding a biological model that recapitulates CSCs and TME may allow a better understanding of tumor onset and progression for testing CSC-based therapies. In this review paper, we examined the CSC and TME characteristics of the human embryonal carcinoma NTERA-2 clonal cell line called NTERA-2 cl.D1 or NT2/D1 cells and discussed their potential utility for research and development of treatments for cancer and central nervous system (CNS) disorders.

METHODS

To probe our hypotheses that NT2/D1 cells display CSC and TME properties key to tumor development, which can serve as a screening platform to test cancer and CNS therapeutics, we conducted a literature review over a 10-year period (2014-2024), focusing on PUBMED and Science Direct published articles on cellular models of cancer, with emphasis on milestone research discoveries on NT2/D1 cells relevant to CSCs and TME. We categorized the studies under pre-clinical and clinical investigations in supporting the existence of CSC and TME features in NT2/D1 cells and providing a laboratory-to-clinic translational basis for cancer and CNS therapeutics.

CONCLUSIONS

NT2/D1 cells stand as a feasible biological model that recapitulates the crosstalk of CSCs and TME, which may critically contribute to our understanding of cancer and CNS biology and therapeutics. Designing therapeutics against CSCs' distinct self-renewal and differentiation capacities within the TME opens new avenues for treating cancers and CNS disorders.

HER2-positive gastric cancer: from targeted therapy to CAR-T cell therapy

Gastric cancer (GC) ranks as the fifth most prevalent cancer on a global scale, with HER2-positive GC representing a distinct subtype that exhibits more intricate biological characteristics. Conventional chemotherapy typically exhibits restricted efficacy in the management of HER2-positive GC. In light of the incessant advancement in molecular targeted therapies, targeting HER2 has emerged as a promising therapeutic approach for this subtype. The advent of antibody-drug conjugates (ADCs) and chimeric antigen receptor T-cell therapy (CAR-T) has furnished novel treatment alternatives for HER2-positive GC. Nevertheless, owing to the pronounced heterogeneity of GC and the complex tumor microenvironment, drug resistance frequently emerges, thereby substantially influencing the effectiveness of HER2-targeted therapy. This article comprehensively summarizes and deliberates upon the strategies of HER2-targeted therapy as well as the underlying resistance mechanisms.

Microenvironmental Drivers of Glioma Progression

Gliomas, particularly glioblastoma (GBM), are among the most challenging brain tumors due to their complex and dynamic tumor microenvironment (TME). The TME plays a pivotal role in tumor progression, immune evasion, and resistance to therapy through intricate interactions among glioma cells, immune components, neurons, astrocytes, the extracellular matrix, and the blood-brain barrier. Targeting the TME has demonstrated potential, with immunotherapies such as checkpoint inhibitors and neoadjuvant therapies enhancing immune responses. Nonetheless, overcoming the immunosuppressive landscape and metabolic adaptations continues to pose significant challenges. This review explores the diverse cellular and molecular mechanisms that shape the glioma TME. A deeper understanding of these mechanisms holds promise for providing novel therapeutic opportunities to improve glioma treatment outcomes.

Tumor dormancy and relapse: understanding the molecular mechanisms of cancer recurrence

Cancer recurrence, driven by the phenomenon of tumor dormancy, presents a formidable challenge in oncology. Dormant cancer cells have the ability to evade detection and treatment, leading to relapse. This review emphasizes the urgent need to comprehend tumor dormancy and its implications for cancer recurrence. Despite notable advancements, significant gaps remain in our understanding of the mechanisms underlying dormancy and the lack of reliable biomarkers for predicting relapse. This review provides a comprehensive analysis of the cellular, angiogenic, and immunological aspects of dormancy. It highlights the current therapeutic strategies targeting dormant cells, particularly combination therapies and immunotherapies, which hold promise in preventing relapse. By elucidating these mechanisms and proposing innovative research methodologies, this review aims to deepen our understanding of tumor dormancy, ultimately facilitating the development of more effective strategies for preventing cancer recurrence and improving patient outcomes.

CALML3-AS1 enhances malignancies and stemness of small cell lung cancer cells through interacting with DAXX protein and promoting GLUT4-mediated aerobic glycolysis

The lncRNA CALML3 antisense RNA 1 (CALML3-AS1) is a biomarker for various cancers, including non-small cell lung cancer (NSCLC). However, the role of CALM3-AS1 in small cell lung cancer (SCLC) is still unclear. Here, we found that the CALML3-AS1 was upregulated in SCLC tissues and cells. SCLC cells (NCI-H69 and NCI-H466 cells) were transfected with small interfering RNA of CALML-AS1 (si-CALML3-AS1) and Death domain-associated protein (DAXX) (si-DAXX) or an overexpression vector of CALML-AS1 (dCas9-CALML3-AS1) and DAXX (dCas9-DAXX). The results showed that silencing CALML3-AS1 inhibited SCLC cell proliferation, colony formation, migration, invasion, and spheroid formation, and reduced the expression of stemness marker proteins (Nanog. Oct4, and Lin28). Moreover, silencing CALML3-AS1 reduced glycolysis rate, glucose utilization, and lactate production, and decreased the levels of key glycolytic regulatory proteins (GLUT1, GLUT4, HK2, and PKM2) in SCLC cells, while overexpression of CALML3-AS1 promoted malignant growth and stemness and enhanced glucose transporters type 4 (GLUT4)-mediated aerobic glycolysis by interacting with DAXX in NCI-H69 and NCI-H466 cells. Silencing DAXX or GLUT4, or treatment with 2-Deoxy-d-glucose (2-DG, a glycolysis inhibitor) reversed the effects of CALML3-AS1 overexpression on aerobic glycolysis, malignant growth, and stemness of SCLC cells. Finally, NCI-H69 cells transfected with CALML3-AS1, sh-CALML3-AS1, and sh-DAXX lentiviral vectors were subcutaneously injected into nude mice to construct xenograft models. Knockdown of CALML3-AS1 or DAXX inhibited tumor growth in SCLC in vivo. In conclusion, CALML3-AS1, an oncogene, promotes the malignancy and stemness of SCLC cells by interacting with DAXX to enhance GLUT4-mediated aerobic glycolysis, thereby promoting SCLC progression.

CCR5 and IL-12 co-expression in CAR T cells improves antitumor efficacy by reprogramming tumor microenvironment in solid tumors

Chimeric antigen receptor (CAR) T cell therapy for solid tumors faces significant challenges, including inadequate infiltration, limited proliferation, diminished effector function of CAR T cells, and an immunosuppressive tumor microenvironment (TME). In this study, we utilized The Cancer Genome Atlas database to identify key chemokines (CCL4, CCL5, and CCR5) associated with T cell infiltration across various solid tumor types. The CCL4/CCL5-CCR5 axis emerged as significantly correlated with the presence of T cells within tumors, and enhancing the expression of CCR5 in CAR T cells bolstered their migratory capacity. Furthermore, single-cell immunoprofiling of tumor tissues revealed that macrophages within the TME primarily interact with CD8+ T cells, impeding their tumor response. However, CAR T cells engineered to secrete Interleukin (IL)-12 can counteract macrophage-mediated immunosuppression and augment T cell functionality. To address these obstacles, we employed esophageal carcinoma as a model to develop mesothelin-targeted CAR T cells co-expressing CCR5 and IL-12 (CARTmeso-5-12), subsequently assessing their antitumor capabilities in vitro and in vivo. The CARTmeso-5-12 cells demonstrated enhanced tumor infiltration due to overexpression of CCR5, and IL-12 secretion further amplified CAR T cell efficacy by attenuating the suppressive influence of tumor-infiltrating macrophages, thus improving tumor eradication.

Anticancer role of flubendazole: Effects and molecular mechanisms (Review)

Flubendazole, an anthelmintic agent with a well-established safety profile, has emerged as a promising anticancer drug that has demonstrated efficacy against a spectrum of cancer types over the past decade. Its anticancer properties encompass a multifaceted mechanism of action, including the inhibition of cancer cell proliferation, disruption of microtubule dynamics, regulation of cell cycle, autophagy, apoptosis, suppression of cancer stem cell characteristics, promotion of ferroptosis and inhibition of angiogenesis. The present review aimed to provide a comprehensive overview of the molecular underpinnings of the anticancer activity of flubendazole, highlighting key molecules and regulatory pathways. Given the breadth of the potential of flubendazole, further research is imperative to identify additional cancer types sensitive to flubendazole, refine experimental methodologies for enhancing its reliability, uncover synergistic drug combinations, improve its bioavailability and explore innovative administration methods. The present review provided a foundation for future studies on the role of flubendazole in oncology and described its molecular mechanisms of action.

Looking ahead to targeting macrophages by CAR T- or NK-cells in blood cancers

INTRODUCTION

The bone marrow microenvironment (BME) is critical for healthy hematopoiesis and is often disrupted in hematologic malignancies. Tumor-associated macrophages (TAMs) are a major cell type in the tumor microenvironment (TME) and play a significant role in tumor growth and progression. Targeting TAMs and modulating their polarization is a promising strategy for cancer therapy.

AREAS COVERED

In this review, we discuss the importance of TME and different multiple possible targets to modulate immunosuppressive TAMs such as: CD123, Sphingosine 1-Phosphate Receptors, CD19/CD1d, CCR4/CCL22, CSF1R (CD115), CD24, CD40, B7 family proteins, MARCO, CD47, CD163, CD204, CD206 and folate receptors.

EXPERT OPINION

Innovative approaches to combat the immunosuppressive milieu of the tumor microenvironment in hematologic malignancies are of high clinical significance and may lead to increased survival, improved quality of life, and decreased toxicity of cancer therapies. Standard procedures will likely involve a combination of CAR T/NK-cell therapies with other treatments, leading to more comprehensive cancer care.

Unveiling the Dynamic Interplay between Cancer Stem Cells and the Tumor Microenvironment in Melanoma: Implications for Novel Therapeutic Strategies

Cutaneous melanoma still represents a significant health burden worldwide, being responsible for the majority of skin cancer deaths. Key advances in therapeutic strategies have significantly improved patient outcomes; however, most patients experience drug resistance and tumor relapse. Cancer stem cells (CSCs) are a small subpopulation of cells in different tumors, including melanoma, endowed with distinctive capacities of self-renewal and differentiation into bulk tumor cells. Melanoma CSCs are characterized by the expression of specific biomarkers and intracellular pathways; moreover, they play a pivotal role in tumor onset, progression and drug resistance. In recent years, great efforts have been made to dissect the molecular mechanisms underlying the protumor activities of melanoma CSCs to provide the basis for novel CSC-targeted therapies. Herein, we highlight the intricate crosstalk between melanoma CSCs and bystander cells in the tumor microenvironment (TME), including immune cells, endothelial cells and cancer-associated fibroblasts (CAFs), and its role in melanoma progression. Specifically, we discuss the peculiar capacities of melanoma CSCs to escape the host immune surveillance, to recruit immunosuppressive cells and to educate immune cells toward an immunosuppressive and protumor phenotype. We also address currently investigated CSC-targeted strategies that could pave the way for new promising therapeutic approaches for melanoma care.

Unlocking the Therapeutic Potential of Oral Cancer Stem Cell-Derived Exosomes

Oral cancer (OC) presents a significant global health burden with rising incidence rates. Despite advancements in diagnosis and treatments, the survival rate for OC patients, particularly those with advanced or recurrent disease, remains low at approximately 20%. This poor prognosis is often due to a small population of cancer stem cells (CSCs) that are capable of self-renewal and immune evasion, playing pivotal roles in proliferation, tumor initiation, progression, metastasis, and therapy resistance. Exosomes, which are nano-sized extracellular vesicles (EVs), have emerged as crucial mediators of cell-to-cell communication within the tumor microenvironment (TME). These vesicles carry diverse molecules such as DNA, RNA, proteins, lipids, and metabolites, influencing various cellular processes. Emerging evidence suggests that CSC-derived EVs significantly promote tumor progression and metastasis and maintain the balance between CSCs and non-CSCs, which is vital for intracellular communication within the TME of oral cancer. Recent reports indicate that oral cancer stem cell-derived EVs (OCSC-EVs) influence stemness, immune evasion, metastasis, angiogenesis, tumor reoccurrence, and drug resistance. Understanding OCSC-EVs could significantly improve oral cancer diagnosis, prognosis, and therapy. In this mini-review, we explore OCSC-derived exosomes in oral cancer, examining their potential as diagnostic and prognostic biomarkers that reflect CSC characteristics, and delve into their therapeutic implications, emphasizing their roles in tumor progression and therapy resistance. However, despite their promising potential, several challenges remain, including the need to standardize isolation and characterization methods and to elucidate exosome-mediated mechanisms. Thus, a comprehensive understanding of OCSC-EVs could pave the way for innovative therapeutic strategies that have the potential to improve clinical outcomes for OC patients.

Cancer-associated fibroblasts and prostate cancer stem cells: crosstalk mechanisms and implications for disease progression

The functional heterogeneity and ecological niche of prostate cancer stem cells (PCSCs), which are major drivers of prostate cancer development and treatment resistance, have attracted considerable research attention. Cancer-associated fibroblasts (CAFs), which are crucial components of the tumor microenvironment (TME), substantially affect PCSC stemness. Additionally, CAFs promote PCSC growth and survival by releasing signaling molecules and modifying the surrounding environment. Conversely, PCSCs may affect the characteristics and behavior of CAFs by producing various molecules. This crosstalk mechanism is potentially crucial for prostate cancer progression and the development of treatment resistance. Using organoids to model the TME enables an in-depth study of CAF-PCSC interactions, providing a valuable preclinical tool to accurately evaluate potential target genes and design novel treatment strategies for prostate cancer. The objective of this review is to discuss the current research on the multilevel and multitarget regulatory mechanisms underlying CAF-PCSC interactions and crosstalk, aiming to inform therapeutic approaches that address challenges in prostate cancer treatment.

Integrative Pan-Cancer Analysis Reveals the Oncogenic Role of MND1 and Validation of MND1's Role in Breast Cancer

Purpose

Meiotic nuclear division 1 (MND1) is a meiosis-specific protein that promotes lung adenocarcinoma progression. However, its expression and biological function across cancers remain largely unexplored.

Patients and Methods

The expression, prognostic significance, mutation status, and methylation profile of MND1 in various cancers were comprehensively analyzed using the TIMER, GTEX, Kaplan-Meier plotter, cBioPortal, and GSCA databases. Additionally, we constructed a PPI network, enrichment analysis and single-cell transcriptomic sequencing to elucidate the underlying mechanism of MND1. Furthermore, we investigated the association between MND1 expression and drug sensitivity using CellMiner. Moreover, we also explored the correlation between MND1 expression and immune infiltration. Finally, we validated the functional role of MND1 in breast cancer through IHC staining, CCK8, EdU, colony formation, and flow cytometry assays.

Results

MND1 has been reported to be highly expressed in Pan-cancer, High MND1 expression was significantly associated with poor prognosis in cancers. Additionally, MND1 mutation frequency is high in most cancers, and its expression correlates with methylation. Furthermore, MND1 expression significantly correlates with immune checkpoint blockade (ICB) markers, including PD-L1, PD-1, and CTLA-4. The PPI network reveals interactions between MND1 and PSMC3IP, BRCA1, and BRCA2. Enrichment analysis and single-cell sequencing indicate that MND1 positively correlates with cell cycle. ROC curve reveals favorable diagnostic efficacy of MND1 in breast cancer. In vitro, MND1 overexpression promotes breast cancer cell proliferation and increases the expression of key cell cycle regulators (CDK4, CDK6, and cyclin D3), accelerating the G1/S phase transition and leading to abnormal breast cancer cell proliferation. The immunohistochemical analysis revealed a robust expression of MND1 in breast cancer tissues, exhibiting a significant positive correlation with PD-L1 and FOXP3.

Conclusion

MND1 is an oncogene and may serve as a biomarker for cancer prognosis and immunotherapy. Targeting MND1 may be a potential tumor treatment strategy.

Exploring Importance and Regulation of Autophagy in Cancer Stem Cells and Stem Cell-Based Therapies

Autophagy is a globally conserved cellular activity that plays a critical role in maintaining cellular homeostasis through the breakdown and recycling of cellular constituents. In recent years, there has been much emphasis given to its complex role in cancer stem cells (CSCs) and stem cell treatment. This study examines the molecular processes that support autophagy and how it is regulated in the context of CSCs and stem cell treatment. Although autophagy plays a dual role in the management of CSCs, affecting their removal as well as their maintenance, the intricate interaction between the several signaling channels that control cellular survival and death as part of the molecular mechanism of autophagy has not been well elucidated. Given that CSCs have a role in the development, progression, and resistance to treatment of tumors, it is imperative to comprehend their biological activities. CSCs are important for cancer biology because they also show a tissue regeneration model that helps with organoid regeneration. In other words, the manipulation of autophagy is a viable therapeutic approach in the treatment of cancer and stem cell therapy. Both synthetic and natural substances that target autophagy pathways have demonstrated promise in improving stem cell-based therapies and eliminating CSCs. Nevertheless, there are difficulties associated with the limitations of autophagy in CSC regulation, including resistance mechanisms and off-target effects. Thus, the regulation of autophagy offers a versatile strategy for focusing on CSCs and enhancing the results of stem cell therapy. Therefore, understanding the complex interactions between autophagy and CSC biology would be essential for creating therapeutic treatments that work in both regenerative medicine and cancer treatment.

Integration of single-cell sequencing and bulk RNA-seq to identify and develop a prognostic signature related to colorectal cancer stem cells

The prognosis for patients with colorectal cancer (CRC) remains worse than expected due to metastasis, recurrence, and resistance to chemotherapy. Colorectal cancer stem cells (CRCSCs) play a vital role in tumor metastasis, recurrence, and chemotherapy resistance. However, there are currently no prognostic markers based on CRCSCs-related genes available for clinical use. In this study, single-cell transcriptome sequencing was employed to distinguish cancer stem cells (CSCs) in the CRC microenvironment and analyze their properties at the single-cell level. Subsequently, data from TCGA and GEO databases were utilized to develop a prognostic risk model for CRCSCs-related genes and validate its diagnostic performance. Additionally, functional enrichment, immune response, and chemotherapeutic drug sensitivity of the relevant genes in the risk model were investigated. Lastly, the key gene RPS17 in the risk model was identified as a potential prognostic marker and therapeutic target for further comprehensive studies. Our findings provide new insights into the prognostic treatment of CRC and offer novel perspectives for a systematic and comprehensive understanding of CRC development.

Cx1Mab-1: A Novel Anti-mouse CXCR1 Monoclonal Antibody for Flow Cytometry

The C-X-C motif chemokine receptor-1 (CXCR1) is a rhodopsin-like G-protein-coupled receptor, expressed on the cell surface of immune cells and tumors. CXCR1 interacts with some C-X-C chemokines, such as CXCL6, CXCL7, and CXCL8/interleukin-8, which are produced by various cells. Since CXCR1 is involved in several diseases including tumors and diabetes mellitus, drugs targeting CXCR1 have been developed. Therefore, the development of sensitive monoclonal antibodies (mAbs) for CXCR1 has been desired for the diagnosis and treatment. This study established a novel anti-mouse CXCR1 (mCXCR1) mAb, Cx1Mab-1 (rat IgG1, kappa), using the Cell-Based Immunization and Screening method. Cx1Mab-1 reacted with mCXCR1-overexpressed Chinese hamster ovary-K1 (CHO/mCXCR1) and mCXCR1-overexpressed LN229 glioblastoma (LN229/mCXCR1) in flow cytometry. Cx1Mab-1 demonstrated a high binding affinity for CHO/mCXCR1 and LN229/mCXCR1 with a dissociation constant of 2.6 × 10-9 M and 2.1 × 10-8 M, respectively. Furthermore, Cx1Mab-1 could detect mCXCR1 by Western blot analysis. These results indicated that Cx1Mab-1 is useful for detecting mCXCR1, and provides a possibility for targeting mCXCR1-expressing cells in vivo experiments.